The fan rotor of a gas turbine engine can have a severe radial unbalance in case of the loss of a fan blade or if a significant blade deformation occurs due to an impact with a foreign object, such as a large bird. This radial unbalance will be in addition to the usual axial and radial loads generated by the fan. The thrust bearing housing must be able to sustain the full load in the event that the front bearing, if any, is compromised and that the low pressure (LP) shaft is severed. A front bearing is provided in some gas turbine engines to support the front of the LP spool. However, a front bearing is usually designed to be frangible in order to protect the major structures from excessive loading during an FBO and FOD event. Since the fan rotor generally overhangs forward of the thrust bearing, the thrust bearing can be cross-cornered during an FBO or FOD event, thereby generating a massive moment load on the thrust bearing housing that supports the outer race of the thrust bearing.
FIG. 3 shows an example of a thrust bearing housing 20′ as found in the prior art. With the prior design, the thrust bearing housing 20′ had no significant hinge point, and the moment loading buckles at the cone at the low diameter. Any hinging occurs on the same side of the flange that the bearing resides. Analytical results from FBO and FOD simulations show that the housing damage is focus low in the cone and plastic strain could exceed the material limits.
Overall, although existing designs of the thrust bearing housing were generally satisfactory, it was still desirable to provide an improved thrust bearing housing having an increased capability of supporting an FBO or FOD event.